1. Field of the Invention
The invention relates to a tire pressure indicator, more particularly to a tire pressure indicator which generates an alarm signal whenever a tire is under- or over-inflated.
2. Description of the Related Art
U.S. Pat. No. 5,001,457 discloses an electronic signal device for a set of pneumatic tires, which signal device includes a pressure gauge attached to each of the pneumatic tires and which transmits an electrical signal whenever the tire is under-inflated. The signal transmitted by the pressure gauge is received by a receiver circuit found inside the driver room of the vehicle. The receiver circuit activates a display means so as to indicate to the driver which one of the tires is under-inflated.
U.S. Pat. No. 5,025,244 and co-pending U.S. patent application Ser. No. 07/704,195, both by the applicant, disclose a tire pressure indicator which generates a light signal when the tire to which the tire pressure indicator is attached is under-inflated.
Note that the above-cited references are capable of generating an alarm signal when the tire is under-inflated. However, none of the above-cited references are capable of generating an alarm signal when the tire is over-inflated.